Objectives ▸ describe clinical/radiological features of paediatric moyamoya (MM).

▸ examine determinants of outcome.

Methods Retrospective notes and radiology review. Logistic regression was used to examine associations with outcome.

Results Of 71 children (median 5.2 y, 48 female), 52 presented with ischaemic symptoms. 26 had a MM risk factor; 5 had positive family history.

Carotid arteriopathy affected 135 hemispheres; 24 patients had posterior circulation involvement. Initial scan showed acute infarction in 26/135 hemispheres and established infarcts in 72/135. Treatment included antiplatelet drugs (57/71) and revascularisation surgery (75/135 hemispheres).

50/71 had recurrence (17 arterial ischaemic stroke (AIS)) within a median of 1 month, of whom 45 went on to surgery. 26/45 surgical patients had further symptoms, AIS in 3. On re-imaging, further infarcts were seen in 24/112 hemispheres and progression of arteriopathy in 25/55 patients.

Outcome was good in 37/69. TIA (OR=0.06, 95% CI=0.01–0.34) or headache (OR=0.10, 95% CI=0.01–0.69) presentation was associated with significantly lower odds of poor outcome than AIS presentation. Having controlled for presentation and MM risk factors, posterior circulation involvement was significantly associated with poor outcome (OR=6.59, 95% CI=1.30–33.45).

Conclusions MM is associated with multiple recurrences, progressive arteriopathy and poor outcome in half of cases, especially with AIS presentation and posterior circulation involvement. Recurrent AIS is rare after surgery but surgery was not a determinant of overall outcome; this could reflect surgical selection criteria or the patients' clinical state at referral.